Safety inks and documents



P 3, 1968 c. o. GUERTIN 3,400,003

SAFETY INKS AND DOCUMENTS Filed Aug. 9, 1966 SET OF ALTERABLE i lPRINTED ELEMENTS a ALTEQ'ZEIE $1228 FELEMENTS j IMPRESSION /4 CYLINDERRUBBE L BLANKET INVENTOR. Cz IFFOAD fl. 'mswrw ATTORNEY United StatesPatent 3,400,003 SAFETY INKS AND DOCUMENTS Clifford D. Guertin, RiverVale, N.J., assignor to American Bank Note Company, New York, N.Y., acorporation of New York Continuation-impart of application Ser. No.270,105, Apr. 2. 1963. This application Aug. 9, 1966, Ser. No. 571,311

5 Claims. (Cl. 117--1) ABSTRACT OF THE DISCLOSURE A printing inkconsisting essentially of coloring matter and a vehicle soluble in waterand lower alcohols and lower ketones, said vehicle consistingessentially of glycerine, sorbitol and water, the glycerine beingpresent in an amount in the range -30% by weight based on said vehicle,the remaining percentages of sorbitol and water being in the weightratio 4:1, said coloring matter including a dye soluble in loweralcohols and lower ketones wherein said lower alcohols and said lowerketones contain not more than 8 carbon atoms per molecule, has beenfound to be especially useful for the preparation of a printed documentsensitive to attempted alteration. A printed document, such as a printedsecurity document, printed with a background provided by theabovedescribed printing ink would be sensitive to and would indicate anattempted alteration with respect to any indicia written thereon bymeans of a typical writing ink, such as a water-soluble and/orbleachable writing ink, or by means of a ball point ink. When indicia onthe printed document written by means of a water-soluble ink are alteredthe printing ink background, since the vehicle from which it is derivedis water-soluble, would be disturbed and would indicate, as a result, anattempted alteration. Similarly, when the indicia on the printeddocument written thereon by means of a ball point ink are subjected toan attempted alteration, such as by means of a lower alcohol or ketone,the printed background material would also be altered or changed, alongwith the ball point ink, with the result that the attempted alterationwould be indicated on the face of the document.

This application is a continuation-in-part of my application Ser. No.270,105, filed Apr. 2, 1963, entitled, Safety Inks and Documents, nowabandoned, and Methods of Printing Documents, which in turn is acontinuation-in-part of my application Ser. No. 12,211 filed Mar. 1,1960, entitled, Safety Inks and Documents, now US. Patent 3,088,841.

This invention relates to safety papers, i.e. printed documents, such asnegotiable instruments, which are adapted for the insertion of names,amounts, etc., by hand and which are sensitive to attempts to alterthese names, amounts, etc., once they have been inserted. The inventionincludes documents having areas printed with inks designed to give therequired sensitivity and inks having the characteristics necessary forsuch documents. By sensitivity to attempted alteration is meant that anattempt to alter the printed document results in a noticeable change inthe appearance of the document so as to alert a person receiving it tothe fact that the document has been altered.

For a long time prior to 1945, most writing inks were water solutionswhose coloring material was either a ferrous salt which oxidized to aferric salt after writing, or an aniline dye, or combinations of both asalt and a dye. The techniques of eradication of such inks wereestablished many years ago. Where the dried ink was water soluble,- suchtechniques simply involved the use of water as a solvent (so-calledwashable ink). Where the dried ink was not water soluble, theeradication techniques employed some type of bleaching reaction. Thebleaching solutions (ink eradicators) for such inks are commonly sold.

Inks consisting of coloring material of one type or another dissolved inwater are still in common use, and are hereinafter referred to asconventional inks. Ball point pens, which came into use about 1945, usea different type of ink. Typically, a ball point pen ink is relativelystiff and heavy and may consist of one of the higher glycols as avehicle, with an aniline dye for coloring material. Many of the ballpoint pen inks cannot be eradicated either by the use of water as asolvent or by the bleaching method. Until recently there has been noknown effective means of eradicating such inks.

Safety papers and safety printing techniques have been developed in thepast which are reasonably sensitive to attempted eradication of one ofthe conventional inks, so as to warn a person to whom an altereddocument was presented that an attempt had been made to alter it. Suchpapers and printing techniques are not sensitive to eradicationtechniques directed at ball point inks. Until recently, no particularditficulty has been encountered with these safety papers and printingtechniques, when used with ball point writing, because there has been nocommonly known effective technique for eradicating the ball point ink.

Recently, banks and other institutions using printed documents of thistype have encountered situations where ball point writing had beensuccessfully eradicated, and it has become apparent that at least someindividuals are aware of techniques for eradicating at least some of theball point pen inks. While the details of all processes which mighteradicate ball point pen inks are unknown, it has been determined thatall processes so far known involve the use, at some stage of theprocess, of a solvent selected from the lower alcohols or lower ketones.By lower is meant that the number of carbon atoms in the particularalcohol or ketone is not greater than eight.

There have been recognized in the past two general techniques oferadication which may be classified as line eradication and sheeteradication. Line eradication involves the application of eradicatingsolution only to the particular line or lines to be eradicated. In sheeteradication, the entire sheet or document is immersed in the solvent orother agent used. The line eradication technique is the one mostfrequently employed in connection with conventional inks. It has beendetermined that the ball point pen inks require, in all the knownprocesses, the sheet eradication technique.

It is also known that time is very important in the ball point inkeradication techniques. To be successful, the eradication much becompleted within a relatively short time, of the order of thirtyseconds. If the eradication has not been completed in that time, thenthe solvent may start to spread the ball point ink into the paper,thereby frustrating the attempted eradication.

A document printed according to the invention described in my US. Patent3,088,841, mentioned above, has one area, which may be the area wherethe name of the payee is to be inserted, wherein background elements(fine lines, dots, etc.) are printed from two complementary plates. Oneof the two plates may print the fine lines in a portion of the areawhich defines a plurality of parallel bars. The other of the two platesmay print the rest of the area, filling in the unprinted spaces betweenthe parallel bars of the first plate. The first plate employs an inkwhich is eradicated by any of the conventional eradication techniques,principally bleaching and/or dissolving in water. The second plateemploys an ink sensitive to any of the new ball point ink eradicationtechniques. Such documents require two impressions for printing thebackground, and the two impressions must be in registry.

An object of the present invention is to provide a printed documenthaving a printed background sensitive to attempted alteration by eitherthe conventional eradication techniques which are useful with waterbased writing inks or by the newer eradication techniques which may beused with ball point pen inks, which background may be printed in asingle impression.

Another object of the invention is to provide an improved singleimpression method of printing such documents.

A further object of the invention is to provide improved inks for use inthe printing of such documents.

The foregoing and other objects of this invention are attained in thepreferred embodiment described herein, by printing two sets ofbackground elements on a document in two different inks, desirably bythe use of a single printing impression. The inks differ as to theirsensitivity to eradication techniques and particularly with respect totheir sensitivit yto techniques employed in the eradication of ballpoint pen inks. Typically, one of the two inks is not affected byattempted eradication, while the other ink is affected either bycomplete disappearance or by a change in color. The two inks arecompatible with each other so that they may be printed over one anotherWhile still wet without causing any blurring or any repellent effectbetween the two inks. In the preferred printing process, the twopatterns of background elements are successively printed on a rubberblanket and the combined patterns are then transferred to the paperdocument in a single printing impression.

Compatibility of the several inks is preferably secured by using thesame vehicle for all the inks but it is a feature of this invention thatby employing the special vehiclecontaining ink herein a wide variety ofother inks, waterbase and oil base may be employed in cooperationtherewith.

Other objects and advantages of the invention will become apparent froma consideration of the following specification and claims, takentogether with the accompanying drawings.

In the drawings:

FIG. 1 is a plan view of a bank check printed in accordance with oneembodiment of the invention;

FIG. 2 is a plan view of a bank check printed in accordance with anotherembodiment of the invention;

FIG. 3 is a diagrammatic view showing printing apparatus for producingthe check of FIG. 2 and illustrating a printing method forming part ofthe invention.

Safety papers prepared in accordance with the invention have printedmatter thereon, which is eradicated by the techniques presently knownfor eradicating ball point pen ink. Typically, the printed matter soeradicated consists of a background of closely spaced fine lines, whichmay appear in any suitable configuration characters, words, geometricfigures, etc. The ink in which at least some of the printed patterns ofthe background appear should be soluble in organic solvents selectedfrom the class having not more than eight carbon atoms and consisting ofthe lower alcohols and lower ketones. There are two principal reasonsfor so limiting the class of organic solvents. One reason is that thealcohol and ketones as defined above are the ones most availablecommercially, and hence most likely to be used by a person attempting toalter a document. Another reason is that the higher ketones and alcoholsdo not act rapidly enough as solvents, and spread the ink into the paperinstead of carrying it away. Consequently, a person seeking to altersuch a document is frustrated if he attempts to use any of the higheralcohols or ketones.

Where more than one ink is used, the two inks must be compatible if asingle impression printing process is to be employed. Compatibility isassured by employing the special vehicle-containing ink in accordancewith this invention. At least one of the inks must include a coloringmatter component soluble in the lower alcohols and lower ketones. Inmany cases, it is desirable to use one ink including a pigment which isinsoluble in the lower ketones and lower alcohols.

Typically, it is desired that the inks and ink components which aresoluble in the lower alcohols and lower ketones be also soluble inwater, since water is utilized as the vehicle in conventionaleradication techniques, including the bleaching techniques. However, insome cases, printed documents may be exposed for long periods of time tothe air in humid climates. In those cases, it is essential that the inkemployed should not be so water soluble that high humidity will make itstart to run and destroy the pattern.

Vehicle I have found only one vehicle which is suitable from thestandpoint of being miscible with the various coloring matters employedin inks manufactured according to the invention and which is alsosoluble in water and in the lower alcohols and ketones. This vehicleconsists essentially of about 20% glycerine, about 64% sorbitol andabout 16% water. These percentages are by weight. The proportion ofglycerine employed in this vehicle may vary from about 10% to about 30%.If the proportion of glycerine is reduced below about 10%, tendencies tocrystallize are observed. If the proportion of glycerine is increasedabove about 30%, the consistency of the vehicle becomes too thin forproper operation on conventional printing presses. The relativeproportions of sorbitol and water should remain about the same (i.e.about of the material other than glycerine should be sorbitol and about20% water).

A printing ink in accordance with this invention having theabove-described vehicle therein results in an ink which is compatiblenot only with water-base inks but also with oil-base inks. Accordingly,a printing ink containing this vehicle can be employed in a singleprinting operation together with another water-base ink or anotheroil-base ink.

Printing inks containing this vehicle also perform satisfactorily on theprinting press and are stable during printing and after being applied tothe paper by the printing press. Also the resulting printed linessupport writing by the conventional writing media without noticeablebleed and feather of the written line. Additionally, the resultingprinted material is stable to handling during use and does not tend tochange in color and effectively responds in the intended manner tofraudulent manipulation of the written material to create a noticeablechange in the appearance of the document.

INK-EXAMPLE I EXAMPLE II This ink may consist essentially of the vehicleasdescribed above and coloring matter consisting essentially of a dye ordyes which are soluble in the lower alcohols and ketones, water soluble,and bleachable. The dye may be a hydrochloride ofphenylpentamethyl-triamido-diphenyl-a-naphthol-carbinol, for example,Victoria Blue.

EXAMPLE III This ink may consist essentially of the vehicle as describedabove and coloring matter consisting essentially of EXAMPLE IV This inkconsists essentially of the vehicle described above and coloring matterconsisting only of pigments which are bleachable and insoluble in waterand in the lower alcohols and ketones.

Printing process-FIG. 3

This figure illustrates diagrammatically apparatus for carrying out asingle impression printing process utilizing inks of the type describedabove. This printing process produces a document such as thatillustrated in FIG. 2, having a background including one set of elementssuch as the solid lines 1 and another set of elements such as the dottedlines 2. Typically, one of the two sets of elements will be printed inink of the type set forth above in Example IV and the other set ofelements will be printed in one of the inks described in Examples I, IIand III. In the apparatus of FIG. 3, cylinders 4 and 5 carry printingplates (not shown) which respectively reproduce the patterns of thelines 1 and 2 in FIG. 2. Inking rollers 6 and 7 respectively pick up inkfrom the ink troughs 8 and 9 and apply the ink to the patterns on theplates carried by the cylinders 4 and 5. The patterns on those cylindersare transferred to an endless rubber blanket 10 which runs over a pairof drive rollers 11 and 12, so that its outer surface comes successivelyinto contact with the printing plates carried by the cylinders 4 and 5.The paper or other sheet material to be printed comes from a supply roll13 and passes through a pair of guide rollers 14 and between animpression cylinder 16 and the blanket 10 at the point where the blanket10 passes over the roller 12. The two patterns transferred to theblanket 10 by the cylinders 4 and 5 are thus transferred to the paperweb 17 at that point. The web 17 passes on to a take-up reel 18.

If the two inks in the ink troughs 8 and 9 are selected from theexamples given above, then these inks are fully compatible and thedeposition of the pattern on the blanket 10 by the roller 4 will not bedisturbed by the deposition of a second pattern by the cylinder 5 eventhough the lines of the second pattern cross the lines of the firstpattern.

It is not necessary that the vehicles in the two inks be exactly thesame but they must be compatible, i.e. one must mix with the other whenboth are spread in successive layers on the rubber blanket surface.Compatibility is assured by employing an ink having the vehicle inaccordance with this invention. The above-described vehicle inaccordance with this invention when incorporated in a water-base inkrenders the same compatible with oil-base inks.

Where one of the patterns is printed in ink according to Example IV,then that pattern is not disturbed or changed in any way by anyeradication, whether it be water eradication, organic solventeradication, or bleaching eradication. If the other ink is Example I,then its dye is removed by the use of an organic solvent eradicationtechnique, leaving the permanent pigment portion of the ink on thepaper, Consequently, the pattern printed in this ink changes color whensuch an eradication is attempted. The use of water eradication orbleaching eradication techniques may remove the dye or not, depending onwhether the particular dye is bleachable and/or water soluble.

If the document has a background printed with one pattern in ink ofExample IV and one in ink of Example II, then the use of any eradicationtechniques, whether it is water eradication, organic solventeradication, or bleach eradication, destroys the Example II patterncompletely.

Whether the document is printed with one pattern in an ink of Example IVand one ink of Example III, then the 5 pattern in Example II ink changescolor upon the application of any eradication technique, due to theremoval of the dye while the pigment remains. For this purpose, it

is of course essential that the dye and the pigment be of differentcolors.

10 Single pattern documentFIG. 1

It is alternatively possible to print safety paper with a singlebackground pattern of a single set of lines, such as shown by the lines19 of FIG. 1. Typically, the lines will be irregularly curved or madewith a fanciful pattern rather than being simple straight lines asillustrated. For the purpose of making such a document, the ink may beselected from any of the Examples I, H and III above. The application oferadication techniques would affect 20 such a paper in the same manneras explained above in connection with the ink examples.

It is also possible to use known vehicles and coloring materials commonin the printing art to produce printing inks which will be bothbleachable and soluble in water and in organic solvents of the classdescribed. Another example of such an ink which has been found suitablefor use in connection with the present invention consists of 50 to 70parts by weight of sulfonated castor oil as a vehicle, 20 to 50 parts byweight of an extender which may be aluminum hydrate, or calcium silicateor magnesium silicate or mixtures thereof, and 6 to 12 parts by weightof coloring material which may be a dye of the diamino-triphenylmethanegroup, for example, Malachite Green.

While I have shown and described certain preferred embodiments of myinvention, other modifications there of will readily occur to thoseskilled in the art, and I therefore intend my invention to be limitedonly by the appended claims.

I claim:

1. A printed document sensitive to attempted alteration comprising anarea adapted to be written upon in ink and having a background ofprinted elements including two superimposed patterns, one of saidpatterns having been printed in a first ink consisting essentially ofcoloring matter and a vehicle soluble in water and lower alcohols andlower ketones, said vehicle consisting essentially of glycerine,sorbitol, and water, the glycerine being present in an amount in therange 10-30% by weight based on said vehicle, the remaining percentagesof sorbitol and water being in the weight ratio 4:1, said coloringmatter including a dye soluble in lower alcohols and lower ketoneswherein said lower alcohols and said lower ketones contain not more thaneight carbon atoms per molecule, and the other said pattern beingprinted in a second ink compatible with said first ink and which isnon-bleachable and insoluble in water and in said lower alcohols andsaid lower ketones.

2. A printed document sensitive to attempted alteration comprising anarea adapted to be written upon in ink and having a background ofprinted elements including two superimposed patterns, one of saidpatterns having been printed in a first ink consisting essentially ofcoloring matter and a vehicle soluble in water and lower alcohols andlower ketones, said vehicle consisting essentially of glycerine,sorbitol, and water, the glycerine being present in an amount in therange 10-30% by weight based on said vehicle, the remaining percentagesof sorbitol and water being in the weight ratio 4:1, said coloringmatter including a dye soluble in lower alcohols and lower ketoneswherein said lower alcohols and said lower ketones contain not more thaneight carbon atoms per molecule and being bleachable and soluble inwater, and a pigment which is non-bleachable, insoluble in water andinsoluble in said lower alcohols and lower ketones,

and the other pattern having been printed in a second ink compatiblewith said first ink but which is non-bleachable and insoluble in waterand in said lower alcohols and lower ketones.

3. A printing ink consisting essentially of coloring matter and avehicle soluble in water and lower alcohols and lower ketones, saidvehicle consisting essentially of glycerine, sorbitol and water, theglycerine being present in an amount in the range 10-30% by weight basedon said vehicle, the remaining percentages of sorbitol and water beingin the weight ratio 4:1, said coloring matter including a dye soluble inlower alcohols and lower ketones wherein said lower alcohols and saidlower ketones contain not more than 8 carbon atoms per molecule.

4. A printin ink in accordance with claim 3 wherein said dye is watersoluble and bleachable.

5. A printing ink in accordance with claim 3 wherein said coloringmatter includes a pigment which is nonbleachable, insoluble in water andinsoluble in said lower alcohols and lower ketones.

References Cited UNITED STATES PATENTS 1,506,144 8/1924 Weeks 11712,305,098 12/1942 Minnear 117-1 3,088,841 5/1963 Guel'tin 1l71 MURRAYKATZ, Primary Examiner.

